Apparatus for continuous and automatic adjustment and control of the stitch length or closeness of loops during operation of knitting and stockings machines



April 10, 1962 K. I. J. ROSEN 3, 3

APPARATUS FOR. CONTINUOUS AND AUTOMATIC ADJUSTMENT AND CONTROL Aprll 10,1962 K. I. J. ROSEN 3,028,738

APPARATUS FOR CONTINUOUS AND AUTOMATIC ADJUSTMENT AND CONTROL OF THESTITCH LENGTH OR CLOSENESS 0F LOOPS DURING OPERATION OF KNITTING ANDSTOCKINGS MACHINES Filed March 30-, 1959 2 Sheets-Sheet 2 Fig. 2 5

VII/ll/l/IIIII/A I 0 7 17 \26 j K l 5 34 g I I961 31 78 26a 1 12 27 i I22 a I 23 E 25 2 l 1% 73 E 33 g .f 30/ V K v INVENTOR. Km I/I ROSENAPPARATUS FOR CONTINUOUS AND AUTO- MATIC ADJUSTMENT AND CONTROL OF THESTITCH LENGTH R CLOSENESS 0F LOGPS DURING OPERATION OF KNITTING ANDSTOCKINGS MACHINES Karl Isac .loel Rosn, Villa Haga, Ulricehamn, SwedenFiled Mar. 30, 1959, Ser. No. 802,735 3 Claims. (Cl. 66-54) Thisinvention relates to an apparatus for automatic and continuous controlof the stitch length or closeness of the loops during operation oftricot or stocking knitting machines.

In the manufacture of fabrics on for instance interlock and rib machinesit is of course very important that the fabric keep its calculated loopcloseness and weight. The costs of the yarn alone is about 75 of thetotal manufacturing costs for average thick underwear of relativelysimple yarns. For heavier fabrics or fabrics containing high qualitycotton, wool, or more expensive artificial fibers, the yarn costs willbe overpoweringly great in relation to the total manufacturing costs.

Weight control is thus a most important factor in the manufacture ofsuch fabrics and it is usually performed by control of the weight persquare unit or by counting the number of loops per length unit. Thepresent invention relates to an apparatus for automatically performingsuch control with an accurateness hitherto unknown by means of anautomatic adjustment of the, stitch length on the different feedersconnected with the machine in question.

On machines having several feeders, it has hitherto been attempted toadjust the different feeders in such a way that they will produceequally large loops. Such an arrangement requires that the feeders takeup equal lengths of yarn during each turn of the machine. In order tomake the loops as equal as possible, there has been used to a greatextent a method based on this condition. Equal yarn quantities aremarked off on the yarn being fed at all the feeders, whereupon themachine is manually rotated until the marks approach the yarn guides andthen observations and adjustments are made. The process is repeateduntil an acceptable evenness is obtained. The method has great drawbacksand on the market there are different instruments for facilitating anaccurate adjustment during the operation of the knitting machine. Mostof said instruments are ordinary yarn speed counters and are thus notideal, since the knitting machines usually vary somewhat in speed duringthe adjustment thereof.

By using a known precision measuring instrument to measure the speed ofthe yarn and then comparing it with the rotation speed of the knittingmachines, it is possible to determine that the variations between theyarn used by the different feeders is as high as 4% even with anaccurate adjustment. On most modern circular knitting machines theadjustment is performed step by step at %2g" of length at a time. Eachstep will constitute a decrease or increase of 1% of the yarnconsumption. Even with the best auxiliary means, the adjustment willoften differ by several steps from the right one, inter alia dependingon varying resistance occurring when the yarn is pulled from the spools,fluctuating temperature and speed of the machine, the feed oflubricating oil etc.

The primary object of the invention is to provide an apparatus whichwill overcome these drawbacks, said apparatus comprising a wheel adaptedto be rotated by the yarn taken in by each feeder, means fortransmitting said motion through suitable gearing to a first gear wheelhaving a threaded shaft threadedly engaged with another Patented Apr.10, 1962 shaft having corresponding threads and which is driven atpredetermined speed in relation to the machine speed, the firstmentioned shaft being connected by means of a motion transmittingelement with the guide for the cylinder cams of the knitting machine.Each difference in the speeds of the two shafts results in an axialchange in position of said shafts in relation to each other, said changein position influencing the stitch length for adjusting the loop sizewhich is predetermined by the rotation speed of the wheel relative tothe speed of the machine.

Carefully made experiments have shown that the apparatus according tothe invention equalizes the use of yarn fed by the different feeders ofthe machine. On a machine having two yarn feeders there were placed,after the automatic adjustment thereof, two spools having each 330 yardsof yarn. When one of the feeders had taken in all the yarn, the otherhad 10" of length left. This involves an adjustment error of only about0.1%.

The apparatus according to the invention can be used in connection withmost types of circular knitting machines, but it is believed that itwill also have great importance in connection with flat knittingmachines. In accordance with the same principl s but with certainchanges and further devices it could be used for stitch, length controlon cotton machines in spite of the fact that the yarn for these machinesis used up not only in a jerky motion but also with different length foreach jerk because of a decrease in the number of loops of the stocking.No doubt, the invention increases the possibility of manufacturingladies stockings having precisely equal length. By means of hithertoknown methods such stockings are sorted and put together in pairsaccording to the length they are given during their manufacture. Suchsorting and matching is greatly facilitated or even eliminated when thestockings are made on machines according to the invention.

In the following the invention will be illustrated with reference had tothe accompanying drawings. In the drawings:

FIG. 1 shows diagrammatically a horizontal projection of a circularknitting machine provided with a stitch length control apparatusaccording to the invention and FIG. 2 shows on an enlarged scale avertical section along the liners aa in FIG. 1 through the control apparatus and discloses some parts of the circular knitting machinediagrammatically.

FIG. 1 will immediately be understood by anybody skilled in the art.Numeral 1 designates a heavy stationary ring in which is carried a ring2 (FIG. 2) driving the cylindrical needle bed and onto which ring 1 thecylinder cam boxes 3 are screwed. Numeral 4 designates the cam boxes ofthe dial having yarn guides 5. The slidable guide members 6 of thecylinder cam boxes are shown without the usual device for theiradjustment since this adjustment has to be carried out automatically bymeans of the control device 7 according to the invention. The controldevice '7 is fastened to the cylinder cam boxes 3. The yarn S is shownrunning a turn around the yarn wheel 9 which is partly surrounded by aconically shaped cap it which facilitates the insertion of the yarn intothe notch of the yarn wheel. Each control apparatus also comprises alever 11 bearing on guide members 6, each of which have upper and lowercam portions 12 and 13 (FIG. 2). The upper portion 12 bears on the feet14 of the cylinder needles to move them down. A gear ring 15 runs in anotch formed in the ring 1. The gear ring 15 is driven by means of aspecial device having a worm and changeable gear wheels (not shown) withan approximate speed of .25 r./min. The speed of the ring could thus bevaried but after each adjustment it is in a fixed relation to therotation of the needle cylinder.

Each control device is provided with a gear wheel 16 the teeth of whichengage the teeth of the gear ring 15 as shown in FIGS. 1 and 2.

The device itself comprises a two-part cover 17 (FIG. 2) enclosing agear transmission for stepping down the speed of a wheel driven by theyarn. The transmission rotates an adjusting means which is coupled withthe guide members 6 with their upper and lower cam portions 12 and 13.

The yarn wheel 9 and the gear wheel 18 are mounted on a thin shaft 24carried in the cap It The lower end of the shaft 24 tapers and restsagainst the fiat upper end of a shaft 25 situated below said shaft 24 inthe cover 17. Two pairs of gear wheels 20 and 22 are freely rotatablymounted on said shaft 25.

A shaft 26 parallel to the shaft 25, is at its lower end provided withleft handed threads and on said shaft 26 there is attached a gear wheel23. Two pairs of gear wheels 19 and 21 are freely rotatably mounted onthe smaller (upper) part of the shaft 26. The threaded part 26a of theshaft 26 is threaded part way into a thicker shaft 27 journalled in thecover 17, and the gear wheel 16 is attached to the lower part of saidshaft 27 by means of a bolt 28. The gear wheel 16 is driven by means ofthe gear ring 15' at the desired speed in relation to the speed ofrotation of the needle cylinder as stated in the aforesaid.

The gearing down may of course be altered in accordance to differentrequirements. In the case here described the gear wheels 1322 have 12teeth each. The gear wheels 1922 each have a larger gear wheel 19a--22afixed thereto for rotation therewith, thus forming gear sets 15!,19a-22, 22a. Larger gear wheels 19a22a each have 42 teeth. The smallgear wheels 18-21 mesh with the larger gear wheels 19a-22a respectively.The gear sets 19, 19a-22, 22a are freely rotatably mounted on the shafts25 and 26 as shown in FIG. 2. From the wheel 18 to the wheel 23, whichalso has 42 teeth and is attached to the shaft 26 and its threaded part26a, the gears mesh five times. The relation between the speed of theyarn wheel and the wheel or the equal to 525 to 1.

The apparatus is filled up to the cover with a special oil low inviscosity. The cover 10 is provided with a disk 32 of unbreakable glassfor preventing the oil from flowing away if the device is moderatelyinclined after the removal of the cylinder 5, said disk also protectingthe oil against dust. The apparatus will have an easy and equal run andbe very durable. In order to prevent leaks there is a packing ring 29around the shaft 27 held in place by a bushing 30. Where the shaft 26penetrates the cover 17, there is positioned a similar packing 31. Thesepackings will probably have an unlimited durability as the shafts 26 and27 rotate with an average speed of only about 4 r./min.

It is evident that if the gear wheel 23, FIG. 2, is blocked and the gearwheel 16 is rotated in a counterclockwise direction according to FIG. 1,the shaft 26 with its left hand threaded part 26a will be backed out ofthe shaft 27. The lever 11 is then moved upwards where it is in contactwith the shaft 26. Because of the fact that the lever 11 is shaped as abalance arm resting on an edge 34, said lever will be tilted in aclockwise direction according to FIG. 2, the guide member 6 therebybeing moved downwards into the cam boxes 3 which results in alengthening of the loop and an increase in the consumption of yarn pereach revolution of the needle cylinder.

On the other hand, if the gear wheel 16 is blocked and the gear wheel 9is turned in a clockwise direction, the shaft 26 will by means of thegear train slowly be 4 threaded into the left hand threaded shaft 27.The spring 33 thereby expands and moves the guide member 6 to a higherposition in the cam box, a shorter loop is thereby obtained and theconsumption of yarn per revolution is decreased.

These two extreme examples illustrate the action of the device. It isevident that as soon as the speed of rotation of the shaft 26 does notcorrespond to the speed of rotation of the shaft 27, the stitch lengthwill be increased or decreased until such a correspondence is reached.

The yarn wheel 9 in the embodiment described above is thought to rotatewith a speed of 2200 r.p.m., said speed being geared down by means ofthe gear wheels 18-23 in such a way that the speed of rotation of thegear wheel 23 on the shaft 26 will be about 4 r.p.m. With such a gearingdown of the speed of movement, the strength of thin, loosely twistedtricot yarns is sufficient for performing the small work required forthreading the shaft 26 into the shaft 27 and it thus decreases the useof yarn in the feeder in question. The somewhat greater work necessaryfor threading said two shafts apart in such a way that the guide member6 is lowered and the spring 33 is compressed to cause an increased useof yarn as a result is not accomplished by the yarn but by the primarymovement of the apparatus, represented by the gear wheel 16 driven bythe gear ring 15. The movement of the shaft 26 which occurs during acounter-clockwise rotation of the shaft 27 at a higher speed than thespeed of the shaft 26 depending on the friction of the left handthreaded screw connection between the shafts will never force the wheel9 to rotate with such a speed that the shaft 26 will be backed out ofthe shaft 27. The device must, however, be constructed so that the minorwork performed by the yarn, when the primary movement of the wheel 16exactly corresponds with the secondary movement of the wheel 23, issomewhat decreased if the feeder in question has a tendency to take uptoo little yarn while the work of the yarn increases somewhat if thefeed has a tendency to take too much yarn in relation to the primarymotion which is defined by the changeable gear wheel which drives thegear ring 15. The ring 15 and the changeable gear wheel may be calledquality wheels as they, together with the thickness of the yarn, definethe stiffness and weight of the fabrics.

There is thus obtained an equalizing effect which will enter into actionbefore there is any real change in the length of the stitch. Whenworking with very weak yarns it is advisable to give the threads of theshafts 26 and 27 a large pitch. Said threads could for instance have adouble or multiple thread so that the primary wheel 16 not only drivesthe secondary wheel 23 and overcomes the friction of the shaft 26 at thejournals and at the packing 31 and at its contact point with the lever11, but will also give to the shaft 24 a slight driving effect. The workwhich has to be performed by the yarn, may thereby be decreased to anydesired extent.

All of the rapidly rotating parts, e.g. 9, 24, 18, and 19 are small andlight in order to diminish their intertial force in such a way that theywill not continue to rotate when the machine is stopped. A suitable oilin the cover 17 is of great value in this connection. The members inquestion have, however, sufficient energy due to their motion that veryquick pulls and jerks which often occur at least in usual tricot yarnswill not reach the knitting point and breaks in the yarns are therebyeliminated.

As has earlier been pointed out the apparatus described works with greataccurateness. It will always control sufiiciently well so that each oneof the feeds takes up exactly the quantity of yarn per machine cycle,i.e. each revolution of the cylinder, which is defined by the qualitywheel which drives ring gear 15. During very careful experiments on acircular knitting machine, a detector or an indicator in contact withthe guide member 6 will show how the latter regains its position definedby the quality wheel with smaller variations in the length than 242043"-will give a compensating adjustment movement.

It is obvious from the foregoing and from the drawing that the adjustingmovement takes place with a decreasing speed. Great errors will decreaserather quickly, whereas the final adjustment will require some time. Ifone of the yarn feeders of the machine is adjusted so that it takes up20% more yarn than the other feeds on a 16" interlock machine having 16feeders, the error will occur as streaks and shadow lines on the knittedfabric. When 8" of the fabric has been knitted, the error can hardly beseen by a human eye but an indicator on the guide member 6 indicatesthat the correct adjustment has been reached only after 20" of thefabric have been knitted. According to the described embodiment thus,about 330 yards must pass the yarn wheel 9 of the apparatus forequalizing an error of about 20%.

What I claim is:

1. An apparatus for automatically and continuously controlling thestitch length during operation of tricot or stocking knitting machineshaving yarn feeds and guide member controlled cams controlling thepositions of the needles to control the stitch length, said apparatuscomprising a wheel rotated by the yarn taken in by each of the yarnfeeds of the machine, means driven by said Wheel for transmitting andgearing down said rotation, a first gear wheel driven by saidtransmitting and gearing down means and having a threaded shaft, asecond gear wheel having an axially threaded shaft with which said shafton said first gear wheel is engaged, said second gear wheel being drivenat a predetermined speed in relation to the speed of the knittingmachine, and a motion transmitting element between the shaft of saidfirst gear wheel and the guide member, whereby each difference in thespeeds of the first and second gear wheels results in an axial change inposition of said shafts in relation to each other, said change ofposition influencing the guide member and the cams controlled thereby.

2. An apparatus as claimed in claim 1 in which said wheel rotated by theyarn and said means driven by said wheel have a small moment of inertia,whereby jerks from Also an only slightly higher friction on yard theyarn spools are taken up and smoothed out and the yarn wheel stopsalmost as soon as the feed of yarn is stopped, when the machine isstopped or the yarn breaks.

3. An apparatus for automatically and continuously controlling thestitch length during operation of tricot or stocking knitting machineshaving yarn feeds and cams controlling the positions of the needles tocontrol the stitch length, said apparatus comprising a Wheel rotated bythe yarn taken in by each of the yarn feeds of the machine, means drivenby said Wheel for transmitting and gearing down said rotation, a firstgear wheel driven by said transmitting and gearing down means and havinga threaded shaft, a second gear Wheel having an axially threaded shaftwith which said shaft on said first gear wheel is engaged, the pitch ofsaid threaded shafts being high so that the force required on the saidwheel for rotating the threaded shaft on said first gear Wheel will besmall and the force for rotating the shaft on the second gear Wheel isgreat, said second gear wheel being driven at a predetermined speed inrelation to the speed of the knitting machine, a motion transmittingelement, one end of which is acted on by the said shaft on the firstgear wheel, a movable guide member engaged by the other end of saidmotion transmitting element and acting on the needle cams for adjustingthe position thereof, and spring means acting on said movable guidemember opposing the action of said motion transmitting elements, wherebyeach difference in the speeds of the first and second gear wheelsresults in an axial change in position of said shafts in relation toeach other, said change of position causing a change in position of saidmovable guide member and the cams moved therbey.

References Cited in the file of this patent UNITED STATES PATENTS2,207,464 Lawson July 9, 1940 2,674,109 Bassist Apr. 6, 1954 FOREIGNPATENTS 756,028 Great Britain Aug. 29, 1956 757,483 Great Britain Sept.19, 1956

